Column change where pull values from acording to the current month

Hi All,

Please tell me if the below are possible and how.

1. I want column "A" in worksheet "SUMMARY" to change the location where it get the values according to the current month. In same workbook I have worksheets with each month of the year. I want Column "A" in "SUMMARY" to get in MAY the values from worksheet "MAY" Column "A" and next month in Jun the same column "A" in "SUMMARY" to populate with values from column "A" in "JUN" worksheet and so on.

2. If new values (customer accounts) are found one month (but were not there previous month) to display in cell "B" in worksheet "SUMMARY" the word "NEW" and other way around if same value one month is not present anymore to display "NO DATA". The values are customer account numbers and each month are customers new and some that left.

I have Excel 2010. Thanks in advance